Conveyor system with automated carriers

ABSTRACT

A conveyorized industrial system includes at least one work station including a heated oven chamber. A fixed, non-powered rail defines a conveyor path including an oven zone in which the rail extends through or over the heated oven chamber. An automated conveyor carrier (ACC) is suspended from the rail by a self-driving trolley having an on-board motor for driving the ACC along the rail, and by at least one additional free-rolling trolley. The ACC further comprises an enclosure containing one or both of an inverter and a battery, the enclosure having a wall defining an interior space of the enclosure. A heat protection system is provided in addition to the wall, the heat protection system operating to limit an internal temperature of the enclosure during transport along the oven zone.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Non-Provisional patentapplication Ser. No. 16/376,142, filed on Apr. 5, 2019, which claimspriority to U.S. Provisional Patent Application No. 62/653,836, filed onApr. 6, 2018, the entire contents of both of which are incorporated byreference herein.

BACKGROUND

Power and Free Conveyor Systems—These systems can be both overhead andinverted. These systems are dual rail systems with one rail providingpower by means of a continuous moving chain and the second railsupporting the load carrying conveyor. The load carrying conveyor can becoupled or decoupled from the continuously moving power chain. The loadcarrying conveyor can be routed on different paths, but the paths aredetermined by a fixed infrastructure of conveyor rail.

Chainless Power and Free Conveyor Systems—This style of conveyor systemis similar to the overhead power and free system, but in lieu of acontinuous moving power chain it implements a rotating friction drivethat can engage and disengage with the load carrier. Many drives areimplemented to make this system operate and an intense electrical andpneumatic infrastructure is required to make if function correctly.

Electrified Monorail Conveyor Systems—These conveyor systems offerindividual carrier control, but require that a power source (electrifiedrail) be run the entire conveyor length.

SUMMARY

In some embodiments, a conveyor system includes a conveyor rail and aplurality of automated carriers. The conveyor rail is a single passive,non-electrified, rail defining a track for the plurality of automatedcarriers. Each of the plurality of automated carriers includes aself-contained power supply and a self-contained drive mechanism forautonomously driving itself along the track defined by the conveyorrail. The conveyor system can be an overhead conveyor or an invertedconveyor.

In some embodiments, each of the plurality of automated carriersincludes a microprocessor operable to control the drive mechanism to setdrive parameters including travel distance, speed, andacceleration/deceleration according to preprogrammed instructions storedwithin a memory of the microprocessor. In some embodiments, one or moreof the plurality of automated carriers is remotely re-programmed from awireless remote controller during operation.

Some embodiments of the present invention provide each of the pluralityof automated carriers with a wireless communication transceiver operableto control the drive mechanism to set drive parameters including traveldistance, speed, and acceleration/deceleration according to a wirelesssignal received from a remote controller.

In some embodiments, each of the plurality of automated carriersincludes an enclosure that is explosionproof, flame-tight, and/ordust-ignitionproof as defined by the NEC. In some embodiments, each ofthe plurality of automated carriers includes an enclosure that ishermetically sealed from the process environment with respect toflammable gases, vapors, and/or liquids. In some embodiments, each ofthe plurality of automated carriers includes an enclosure having anouter housing and a heat insulation layer.

In some embodiments, the conveyor system includes an intersectionwhereby an incoming automated conveyor carrier has the option of atleast two outlet paths from a single switching point. The switchingpoint includes a drive system for translating or rotating a railportion. The drive system for the switching point includes no drivesource of its own and is operated by the self-driving trolley of theautomated conveyor carrier.

In some embodiments, an automated conveyor carrier includes twoself-driving trolleys, and the conveyor system includes a branch railthat extends parallel to a main rail so that driving of the twoself-driving trolleys on the main and branch rails turns the loadcarried by the automated conveyor carrier to a perpendicular orientationfor enhanced close packing. In some constructions, the load densityafforded by turning the loads is in excess of what is physicallypossible with only the main rail.

In some embodiments, the conveyor rail includes a straight portionleading to a curved portion, and the conveyor system is operated toaccelerate the automated conveyor carriers leading into the curvedportion to generate sufficient gaps to avoid collision when navigatingthe curved portion. In some embodiments, the automated conveyor carriersare accelerated through at least an upstream part of the curved railportion.

In some embodiments, operation of the conveyor system includesoscillating a first automated conveyor carrier back and forth along therail at a work station, while a second adjacent automated conveyorcarrier on the rail is stopped or conveyed along a first direction.

In some embodiments, operation of the conveyor system includes settingor changing a running speed of an automated conveyor carrier through afirst work station based on at least one characteristic of the loadsupported. The characteristic can be weight. The weight can berepresented by data provided to the automated conveyor carrier or can bemeasured.

In one aspect, the invention provides a conveyor system comprising afixed, non-powered rail defining a conveyor path, an automated conveyorcarrier (ACC) supported by the rail, and a sleep mode module on-boardthe ACC. The ACC includes an on-board motor, an on-board electricalpower source, and an on-board controller selectively powering theon-board motor, the on-board controller comprising an inverterconfigured to power the on-board motor from the on-board electricalpower source according to a drive signal from the on-board controller,and a wireless communication module configured to communicate electricalsignals with at least one external wireless device. The sleep modemodule includes a secondary wireless communication module and aprocessor, the sleep mode module configured to selectively turn on andturn off power from the on-board power source to the on-boardcontroller. The ACC is operable in a first mode to power the on-boardmotor and drive the ACC along the rail according to the drive signalfrom the on-board controller. The ACC is operable in a second mode inwhich the on-board controller is actively energized, without driving theACC along the rail. The ACC is operable in a third mode of operation,which is a sleep mode in which power to the on-board controller is shutoff and the secondary wireless communication module is powered towirelessly monitor for a wake signal, the sleep mode module configuredto wake the ACC from the sleep mode by re-establishing power to theon-board controller in response to the wake signal.

In one aspect, the invention provides a method of operating a conveyorsystem. A fixed, non-powered rail is provided defining a conveyor path,the rail supporting an automated conveyor carrier (ACC) comprising anon-board motor, an on-board electrical power source, and an on-boardcontroller selectively powering the on-board motor, the on-boardcontroller comprising an inverter powering the on-board motor from theon-board electrical power source according to a drive signal from theon-board controller, and a wireless communication module communicatingelectrical signals with at least one external wireless device, the ACChaving a load suspended therefrom. The ACC is operated in a first modeto power the on-board motor and drive the ACC along the rail accordingto the drive signal from the on-board controller. The ACC is operated ina second mode in which the on-board controller is actively energized,and the ACC remains idle without movement along the rail. The ACC istransitioned from the second mode into a third mode of operation, whichis a sleep mode in which power to the on-board controller is shut off. Asecondary wireless communication module on-board the ACC wirelesslymonitors for a wake signal, the secondary wireless communication modulere-establishing power to the on-board controller to wake the ACC fromthe sleep mode in receipt of the wake signal.

In one aspect, the invention provides a method of operating a conveyorsystem. A load is suspended from an automated conveyor carrier (ACC),and the ACC is suspended from a fixed, non-powered rail defining aconveyor path. The automated conveyor carrier (ACC) is driven along therail by transmitting electrical power from an on-board battery pack ofone or more batteries to an on-board motor under the control of anon-board controller. Secondary power is provided to the ACC whilesuspended from the rail along the conveyor path, the secondary powerbeing provided by: on an outside of a first enclosure containing theon-board battery pack, disconnecting the motor from the on-boardcontroller and the on-board battery pack, coupling a secondary batteryand a secondary controller to the ACC, and connecting power between thesecondary battery and the motor through the secondary controller. TheACC is driven along the rail by transmitting electrical power from thesecondary battery to the motor through the secondary controller.

In one aspect, the invention provides a conveyor system including afixed, non-powered rail defining a conveyor path, and an automatedconveyor carrier (ACC) supported by the rail and drivable along the railby an on-board motor in a self-driving trolley of the ACC, the motorpowering a drive wheel. The rail defines a first section and a secondsection separate from the first section, and the conveyor system isadapted to provide a first amount of traction for the ACC on the rail inthe first section and a second amount of traction, greater than thefirst amount of traction, in the second section.

In one aspect, the invention provides a method of constructing aconveyor system, the method including decommissioning an existingconveyor system by removing electrification or a powered chain from aconveyor rail, and removing unpowered carriers from the rail. Anautomated conveyor carrier (ACC) is installed onto the rail so that adrive wheel of a self-driving trolley of the ACC is put into contactwith the rail. A battery is installed on the ACC. Electrical connectionis established from the battery to the self-driving trolley.

In one aspect, the invention provides a conveyor system including afixed, non-powered rail defining a conveyor path including an oven zonein which the rail extends through or over a heated oven chamber. Atleast one automated conveyor carrier (ACC) is suspended from the rail bya self-driving trolley having an on-board motor for driving the ACCalong the rail, and by at least one additional free-rolling trolley. TheACC further comprises an enclosure containing one or both of an inverterand a battery, the enclosure having a wall defining an interior space ofthe enclosure. An active or passive heat protection system is providedin addition to the wall, the heat protection system operating to limitan internal temperature of the enclosure during transport along the ovenzone.

In one aspect, the invention provides a method of operating a conveyorsystem. A fixed, non-powered rail is provided defining a conveyor path,the rail supporting first and second consecutive automated conveyorcarriers (ACC), each of which includes a motor-powered self-drivingtrolley. A first load is suspended from the first ACC, and a second loadis suspended from the second ACC. The first and second ACCsindependently drive along the rail by executing instructions fromindependent on-board controllers of the first and second ACCs. A firstspacing between the first and second ACCs is maintained through a firstsection of the rail, and the first ACC accelerates away from the secondACC to increase the spacing from the first spacing to a second spacingfor navigating a second section of the rail, the second section being acurved section.

In one aspect, the invention provides a method of operating a conveyorsystem, including providing a fixed, non-powered first rail defining aconveyor path, the first rail supporting first and second trolleys of afirst carrier, at least one of which is a self-driving trolley includingan on-board motor and electrical power source. The first carrier isconveyed under its own power such that the second trolley trails thefirst trolley along the first rail with a load bar extendedtherebetween, the first carrier defining a length measured along alongitudinal extent of the first rail and a width measured transverse tothe longitudinal extent of the first rail. The first carrier is conveyedto a branch point where a second rail branches from the first rail. Thefirst trolley is conveyed along the first the rail and the secondtrolley is conveyed along the second the rail to turn the first carrierso that it is conveyed with its width in line with the longitudinalextent of the rail and with the load bar traversing between the firstand second rails. The width is substantially less than the length suchthat the occupancy of the first carrier along the rail is substantiallyreduced by turning the first carrier.

In one aspect, the invention provides a conveyor system including afixed, non-powered rail defining a conveyor path, and a plurality ofautomated conveyor carriers (ACC) supported on the rail to be movablealong the conveyor path. Each of the plurality of ACCs includes anon-board motor and an on-board electrical power source selectivelypowering the on-board motor to drive the ACC along the rail, at leastsome of the plurality of ACCs having respective loads suspendedtherefrom. Each of the plurality of ACCs operates to power the on-boardmotor from the on-board electrical power source under the direction ofinstructions programmed to a local controller on the respective ACC.Each of the local controllers of the respective ACCs is programmed tocarry out independent power level management for its own on-boardelectrical power source, including an adaptive low power indicator thatcommunicates a low power status that is based in part on the power levelof the on-board battery and further based in part on a location of therespective ACC along the conveyor path and/or a weight of the respectiveload suspended therefrom.

Other aspects of the invention will become apparent by consideration ofthe detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a portion of a conveyor system includingan automated conveyor carrier according to an embodiment of the presentinvention.

FIG. 2 is a perspective view of a driven portion of the automatedconveyor carrier of FIG. 1 .

FIG. 3 is a perspective view of a non-driven portion of the automatedconveyor carrier of FIG. 1 .

FIG. 4 is a perspective view of a self-driving trolley of the automatedconveyor carrier driven portion of FIG. 2 .

FIG. 5 is a perspective view of an upper portion of the self-drivingtrolley having a position-tracking sensor and a charging contact inphysical and electrical connection with a charging contact of a chargingstation.

FIG. 6 is a front view of the self-driving trolley, including a sensorconfigured to monitor the surroundings in front of the automatedconveyor carrier.

FIG. 7 is another perspective view of the self-driving trolley.

FIG. 8 is a perspective view of a drive unit of the self-drivingtrolley.

FIG. 9 is a cross-section view illustrating a pre-tensioning of themotor unit against a rail of the conveyor system.

FIG. 10 is a perspective view from above the charging station, as itaccommodates the self-driving trolley.

FIG. 11 is a perspective view from alongside the charging station, as itaccommodates the self-driving trolley.

FIG. 12 is a perspective view of the interior of an electronicsenclosure of the automated conveyor carrier, and a schematicrepresentation of a control system in communication with a plurality ofautomated conveyor carriers.

FIG. 13 is a perspective view of a self-driving trolley according to analternate construction.

FIG. 14 is a plan view of the conveyor system, illustrating a pluralityof work stations for work pieces conveyed by the conveyor system, alongwith alternate conveyor rail paths and a charging station.

FIG. 15 is a perspective view of a portion of the conveyor systemincluding an automated conveyor carrier conveying one or more workpieces through a slot top oven or furnace.

FIG. 16 is a plan view of a portion of the conveyor system includingclose-packed automated conveyor carriers in a straight conveyor portionprior to a curved conveyor portion.

FIG. 17 is a plan view of a portion of the conveyor system including arotary turntable conveyor portion.

FIG. 18 is a plan view of a portion of the conveyor system including anelevator conveyor portion.

FIG. 19 is a plan view of a portion of the conveyor system including aparallel secondary rail to provide load turning and enhancedclose-packing of automated conveyor carriers.

FIG. 20A is a schematic view of a heat-shielded electronics enclosure.

FIG. 20B is a schematic view of an insulated heat-shielded electronicsenclosure.

FIG. 20C is a schematic view of an electronics enclosure including apassive heat absorbing device.

FIG. 20D is a schematic view of an electronics enclosure including anactive air conditioning system.

The present invention is further described with reference to theaccompanying drawings, which show an embodiment of the presentinvention. However, it should be noted that the invention as disclosedin the accompanying drawings is illustrated by way of example only. Thevarious elements and combinations of elements described below andillustrated in the drawings can be arranged and organized differently toresult in constructions which are still within the spirit and scope ofthe present invention.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the accompanyingdrawings.

FIG. 1 illustrates a conveyor system 20 including a conveyor track orrail 24 and at least one carrier assembly 28, or simply carrier 28. Thecarrier 28 includes at least one component (referred to herein as“trolleys”) engaged with the rail 24 to follow a path defined by therail 24 through a process (e.g., a treatment such as cleaning, painting,electroplating, powder coating, etc.). As illustrated, the carrier 28 isan Automated Conveyor Carrier (ACC) having a self-driving trolley 32. Inaddition to the self-driving trolley 32, the ACC 28 may further includeone or more additional free-rolling trolleys 36, with the trolleys 32,36 supporting a load bar 40 on which a work piece support structure 44such as hook(s), rack(s), or basket(s) is mounted to transport loads orwork pieces 48 for conveyance. The load bar 40 can be supported directlyor indirectly by the trolleys 32, 36. As illustrated, the load bar 40 issupported indirectly by the trolleys 32, 36 by intermediate load bars40A, 40B, each of which is secured between a corresponding trolley set(e.g., pair). Each intermediate load bar 40A, 40B is coupled to the loadbar 40 with a joint 42, such as a swivel joint. Additional joints 42 areprovided as couplings between the intermediate load bars 40A, 40B andthe respective trolleys 32, 36 so that curves in the conveyor rail 24can be navigated. The first trolley set, shown on the right side of FIG.1 , includes the self-driving trolley 32 and one free-rolling trolley 36supporting the first intermediate load bar 40A. The second trolley set,shown on the left side of FIG. 1 , includes two free-rolling trolleys 36supporting the second intermediate load bar 40B. Aspects of theinvention can also be realized in constructions having a single trolleypair supporting the load bar 40 (with or without intermediate load bars40A, 40B), or one or more trolley sets including trolleys numberinggreater than two. As discussed in further detail below, each trolley 32,36 can include one or more wheels for rolling along the rail 24. In theillustrated construction where the load bars 40, 40A, 40B and the workpieces 48 are suspended to hang by gravity below the rail 24, theintermediate load bars 40A, 40B are upper load bars and are coupled to atop edge of the load bar 40. Any or all of the load bars 40, 40A, 40Bcan have an I-beam or modified I-beam cross-section, an example of whichis further illustrated in FIG. 9 , although other geometries areoptional, such as hollow-box and C-channel, among others.

Although the ACC 28 may be operated as a “tugger” in which theself-driving trolley 32 is positioned at a leading end of the ACC 28, itis also conceived that the ACC 28 may operate, at times orpredominantly, as a “pusher” in which the self-driving trolley 32 ispositioned at a trailing end of the ACC 28. In fact, the self-drivingtrolley 32 may be located anywhere along the length of the ACC 28, andin some cases multiple self-driving trolleys 32 may be used in one ACC28, multiple ACCs 28 may be linked together, and/or the self-drivingtrolley 32 of a given ACC 28 may be surrounded fore and aft byfree-rolling trolleys 36.

The ACC 28 allows complete individual control of the carrier in path,speed, and acceleration and deceleration. The ACC 28 is electricallypowered for driving itself along the conveyor rail 24, and theelectrical drive power is supplied by one or more (e.g., fourseries-connected 12-volt) batteries 50 (e.g., lead acid, or lithium-ion)of the ACC 28. The batteries 50 are located on-board the ACC 28 (e.g.,within a housing or enclosure 52 thereof) to establish a self-containedpower source that is not dependent upon energy supply from the conveyorrail 24 or anything external to the ACC 28, such as an additional powersupply rail, during operation. The enclosure 52 having the batteries 50moves with the drive end of the ACC 28—in other words, the end havingthe self-driving trolley 32. However, the enclosure 52 is not fixedsecurely to the self-driving trolley 32. Rather, the enclosure 52 can besecurely fixed to the intermediate load bar 40A (e.g., through one ormore standoff rails 54, FIGS. 2 and 4 ). Thus, the joints 42 allow alimited amount of swiveling between the enclosure 52 and the respectivetrolleys 32, 36. The enclosure 52 is positioned between the trolleys 32,36 of the drive end of the ACC 28. As such, the enclosure 52 spans overtop of the joint 42 that couples the intermediate load bar 40A and themain load bar 40. In some constructions, as shown, the enclosure 52extends along a majority of the length of the intermediate load bar 40A.As discussed further below, the enclosure 52 may also contain furtherelectronics, rather than just the batteries 50. The electronics caninclude a plurality of devices of different types and functions, and maybe related to the driving control of the self-driving trolley 32 andparticularly the delivery of power from the batteries 50 to a motor 204of the self-driving trolley 32. The batteries 50 can be chargedperiodically at a charging station or simply charger 66, as furtherdescribed below, which may be located along a portion of the rail 24that is actively utilized for ACC transport between functional workstations or work locations in a factory floor setting, or alternately,remote therefrom although connected.

Implementing the conveyor system 20 having the ACC 28 requires veryminimal electrical and pneumatic infrastructure and eliminates the needfor power and free conveyor drives and take-ups. Installation time canbe considerably reduced over the other styles of power and free railconfigurations. The conveyor system 20 with one or more of the ACCs 28can be used in an industrial setting in conjunction with automatedguided vehicle systems and with traditional conveyor technology,including but not limited to monorail, floor conveyor, power & free,etc. For example, any one or more of these other systems can be used todeliver and/or pick up parts to/from the conveyor system 20. In someconstructions, the invention includes construction of the conveyorsystem 20 by retrofitting a pre-existing powered-rail conveyor system(e.g., a power and free conveyor, chainless power and free conveyor, orelectrified monorail conveyor). In such a construction, the method caninclude the removal of some or all of the power lines within or alongthe rails 24, as they are unnecessary with the ACCs 28. In other words,the conveyor system 20 can be constructed by a process includingdecommissioning an existing conveyor system by removing electrificationor a powered chain from a conveyor rail, and removing unpowered carriersfrom the rail 24. In other constructions, the conveyor system 20 may bebuilt as-new, without utilizing prior-used conveyor infrastructure.

In some embodiments, the conveyor system 20 can include a plurality ofcarriers 28 (hundreds, or even thousands), and all of the carriers inthe system can be ACCs 28 so that each and every carrier within thesystem is operable to drive itself along the conveyor rail 24. The fixedinfrastructure of rails extending along the conveyor path can be limitedto just the single conveyor rail 24, which is a passive rail merelysupporting the ACCs 28 to define the path. The conveyor rail 24 can be asimple structural element such as a channel or beam, for example, anI-beam. The rail 24 is not equipped to transmit drive forces or theenergy for driving the ACCs 28 during conveyance. Rather, each ACC 28moves itself along the conveyor rail 24 by supplying electrical energyfrom the on-board batteries to a drive unit including one or more motorscoupled to one or more wheels of the self-driving trolley 32. Thus, eachself-driving trolley 32 has at least one drive wheel as discussedfurther below. In addition to a drive wheel(s), each self-drivingtrolley 32 may also have one or more non-driven or “free” wheels, whichmay be referred to as rollers or idle rollers. Each self-driving trolley32 can include a single motor or multiple motors. The self-drivingtrolleys 32 may be devoid of any steering mechanism (e.g., steerablewheels or differential left-right drive) as the conveyor rail 24 definesthe travel path(s).

The self-driving trolley 32 and associated hardware are described infurther detail with respect to FIGS. 2 and 4-9 . The trolley 32 isadapted with one or more rollers 56 coupled to a trolley frame 200 inaddition to a motor frame 202 supporting a motor 204 (e.g., electricmotor, particularly an AC permanent magnet motor). An inverter 206 onthe ACC 28 (e.g., positioned in the enclosure 52 with the batteries 50)operates to convert DC battery power into an AC power supply for themotor 204. A motor power cable 120 (FIG. 4 ) provides power (e.g.,three-phase AC) from the inverter 206 to the motor 204. The motor powercable 120 can extend continuously between the inverter 206 and the motor204, penetrating the wall of the enclosure 52, or alternately, caninclude a quick-disconnect (e.g., plug-in socket) feature at theenclosure 52. Additional electrical connections between the electronicsin the enclosure 52 and the motor 204 (e.g., the inverter 206 to anencoder, a brake, and a thermistor of the motor 204) are established byadditional wires routed through a flexible conduit 124 (FIG. 2 ) thatextends between the enclosure 52 and the self-driving trolley 32,particularly the trolley frame 200. The motor 204 is manufactured aspart of a drive unit 208 (FIG. 8 ) that includes not only the motor 204,but also an integral gearbox 212 and a drive wheel 216. The drive wheel216 is separate from the rollers 56. The gearbox 212 reduces the outputspeed and increases torque from the motor 204. The drive wheel 216, anouter surface of which is of urethane construction in someconstructions, may be positioned at least partially between the motor204 and the gearbox 212. The drive wheel 216 can have an outer diameterlarger than one or both of the motor 204 and the gearbox 212.

As shown in FIGS. 6, 7, and 9 , one or more springs 220 are coupledbetween the trolley frame 200 and the motor frame 202 (to which thedrive unit 208 is fixed) to bias the drive unit 208 toward the rail 24in a direction perpendicular to the lengthwise conveyance directiondefined by the rail 24. The springs 220 operate to exert a bias forcethat increases traction between the drive wheel 216 and thecorresponding contact surface 224 of the rail 24. The contact surface224 is provided as a lower or bottom surface of a lower or bottom web228 of the rail 24. As shown, with the I-beam cross-section of the rail24, the web 228 is a bottom horizontal web of the rail 24. In additionto the bottom horizontal web 228, the rail 24 further includes an upperor top web 232 (e.g., horizontal top web that is parallel to and spacedfrom the web 228) and an additional web 236 (e.g., central vertical webperpendicular to webs 228, 232) interconnecting the bottom and top webs228, 232. The bottom web 228 is the web nearest the conveyed work pieces48, and the contact surface 224 faces the work pieces 48 and the ground(earth) in the illustrated construction. As illustrated, one coil spring220 biases the drive wheel 216 and presses it onto the rail contactsurface 224, but other numbers, types, and arrangements of springs arealso contemplated, and these parameters may vary depending on the typeof rail, the intended loads to be carried by the ACC 28, among otherfactors. The above-described arrangement results in the bottom web 228being trapped or pinched between the drive wheel 216 and at least oneroller 56 on an upper side of the bottom web 228 (e.g., exactly oneroller 56 per side of the central vertical web 236, with these tworollers having a common rotational axis). FIG. 13 illustrates analternate construction in which a self-driving trolley 1032 includes atrolley frame 1200 supporting multiple pairs of rollers 56 definingrespective rotational axes that are longitudinally spaced from eachother.

The total traction between the drive wheel 216 and the contact surface224 is related to the ACC's 28 ultimate load-carrying capacity. Forexample, the available output capacity of the motor 204 (and with it thegearbox 212) alone may not guarantee the ability of the ACC 28 to tow agiven load along the conveyor rail 24, if there is insufficient tractionfor the drive forces to be transmitted between the surface of the drivewheel 216 and the contact surface 224. Further, total traction is afunction of the normal force between the drive wheel 216 and the contactsurface 224, which in turn, is a function of the compression of thespring(s) 220. In order to alter the available traction of theself-driving trolley 32, an adjustment member 240 is operable to varythe loading of the spring(s) 220. The adjustment member 240 as shownincludes a nut threaded to a shaft 242 that extends between respectiveportions of the trolley frame 200 and the motor frame 202 thatcooperatively define a packaging space for the spring(s) 220. As such,tightening of the nut 240 on the shaft 242 further compresses thespring(s) 220 to further load the drive wheel 216 against the contactsurface 224 of the rail 24. On the contrary, loosening the nut 240 onthe shaft 242 reduces spring compression to reduce loading of the drivewheel 216 so that slippage will occur at relatively lower loads. In someconstructions, the adjustment member 240 is merely manually adjustableby a technician (e.g., with a wrench during stoppage or deactivation ofthe conveyor system 20), while in other constructions, the adjustmentmember 240 is remotely and/or automatically adjustable to vary thetraction of the self-driving trolley 32. In one such construction, anactuator 246 such as an electric motor adapted to turn the adjustmentmember 240 is provided and connected to receive command signals from acontroller 248. The controller 248 can be a localized, or “on-board”,controller dedicated for this purpose, or may incorporate additionalfunctions as well. As illustrated, each controller 248 is an on-boardcontroller of a particular ACC 28 dedicated to driving that ACC. Thecontroller 248 comprises a variable frequency drive (VFD) including theinverter 206 and a processor 312 (e.g., embedded microprocessor). Thecontrollers 248 of the various ACCs 28 within the conveyor system 20form one part of an overall control system for operating the ACCs 28.The controller 248 can contain programmable, executable instructions forcommanding the actuator 246 to adjust (up or down) the loading of thedrive wheel 216 so that overall traction is increased or decreased. Theinstructions can allow different sections of the conveyor system 20 havedifferent traction conditions effecting different load-carryingcapacities. In other words, different sections of the conveyor system 20will have different slip limits. Furthermore, this functionality neednot be limited to designated or fixed sections of the conveyor system20, and may alternately or additionally be manipulated conditionally onone or more parameters (e.g., “on the fly”).

Although the above description details the ability of the adjustmentmember 240 to vary the slip limit, another manner of varying the sliplimit is to vary a thickness T of the bottom web 228 that is pinchedbetween the upper rollers 56 and the drive wheel 216 as this will alsohave the effect of further loading the spring(s) 220. Designatedsections of the rail 24 can be intentionally thickened or built-up byadding one or more thin strips of sheet material (e.g., adhesive-backedsheet metal). Additionally or alternatively, designated sections of therail 24 can be worked by subtractive methods (e.g., grinding, sanding,milling, etc.) to reduce the web thickness T. In some constructions, oneor more surfaces of the web 228 engaged by the upper rollers 56 or thedrive wheel 216 can be intentionally modified to provide an enhanced orreduced coefficient of friction. For example, designated sections(whether or not the web thickness T is also altered) along the rail 24may be pressed, machined, etc. to impart texture or roughness exceedinga nominal texture or roughness of the rail 24. Such sections are thensubject to increased load-carrying capacity and have a higher sliplimit. Alternately or additionally, designated sections along the rail24 may be polished or have a friction-reducing agent applied in order tolocally decrease the load-carrying capacity and induce slippage at lowerlimits. Any one or more of these steps can be carried out as part of amethod of retrofitting an existing conveyor system (without poweredcarriers) into the conveyor system 20 designed for use with the ACCs 28,or alternately, for an original installation of the conveyor system 20.

Although additional traction and improved load-carrying capacity of theACC 28 may be highly desirable (e.g., as a means to avoid other costlysolutions such as upsizing components and/or the use of more exoticmaterials), there are cases in which lower limit slippage between thedrive wheel 216 and the contact surface 224 is desirable. For example,in a given conveyor installation in an industrial space, part of theindustrial space may be accessible by other equipment and/or humanworkers. Such factors may introduce the possibility of collision of somepart of the ACC 28, or its payload. Absent other measures, there mayalso be a remote possibility of collision between a consecutive pair ofthe ACCs 28 on the rail 24. In any collision circumstance, an abundanceof traction between the ACC 28 and the rail 24 is not of benefit, butrather introduces greater potential for harm to equipment and/orpersonnel. Thus, certain areas may be designated as areas of potentialcollision or “safety zones” along the rail 24, and these safety zonesmay have a lesser amount of available traction and thus lower sliplimits and lower load-carrying capacity than other zones. As such, inthe event of collision, a driving ACC 28 may merely start slipping inplace along the rail 24 rather than pulling itself further along. Ofcourse, the conveyor system 20 can also include a number of integratedanti-collision means that are configured to avoid collisions in thefirst place (e.g., by detection with a sensor and signaling the stoppageof the ACC 28). In some constructions, the ACC 28 may, through operationof the controller 248, identify entry into a safety zone andautomatically respond by transforming into a reduced-tractionconfiguration. This can be accomplished through automatic manipulationof the adjustment member 240. In some aspects, the invention includessetting the pressing force on the drive wheel 216 in accordance with theload carried by the ACC 28, such as at the time of setup or loading, sothat the resulting traction is only slightly above the minimum amount ofrequired traction to move the load carried (e.g., not more than 10percent above minimum, or not more than 20 percent above minimum). Insome cases, the ACCs 28 include load sensors that automatically detectthe load applied, and the controller 248 operates to set the pressingforce on the drive wheel 216 automatically in accordance with themeasured load.

For periodic charging of the batteries 50 of the ACC 28, there are oneor multiple chargers 66 positioned adjacent the rail 24. For example,each charger 66, an example of which is illustrated in FIGS. 10 and 11 ,can be positioned above the rail 24. The charger 66 can be fixed withrespect to the rail 24. In other constructions, the charger 66 can beadjustably positioned, or adapted for movement between differentlocations along the rail 24, for example during operation of theconveyor system 20 in response to monitored location-based chargingneeds. The charger 66 includes a plurality of charging contacts 250 inelectrical communication with a power source, such as grid powersupplied to the facility housing the conveyor system 20. The chargingcontacts 250 can be spaced across the rail 24 such that positivecontact(s) 250 are on one side of the rail 24 and negative contact(s)250 are on the opposite side of the rail 24. Thus, in plan view, thecharging contacts 250 may be symmetrically positioned about the rail 24.The charger 66 may also include additional electronics adapted toincrease voltage and/or condition the charging current supplied to thecharging contacts 250 when charging the batteries 50. The chargingcontacts 250 can be constructed of a metal of high electricalconductivity (e.g., solid copper or copper laminations). The chargingcontacts 250 include at least one positive contact and at least onenegative contact, and in some constructions multiple pairs of each. Inorder to interface with the charging contacts 250 of the charger 66, theACC 28 includes mating charging contacts 254 (e.g., plates, bars, etc.).As illustrated, the charging contacts 254 are provided on theself-driving trolley 32 to be on opposite lateral sides of the rail 24.The point of contact between the charging contacts 250, 254 can bewithin the height of the rail 24 in side view. As such, the point ofcontact between the charging contacts 250, 254 can be below the topsurface of the rail 24. The charging contacts 250, 254 are adapted toautomatically couple and establish electrical connection automaticallyby bringing the trolley 32 having the charging contacts 254 into aposition along the rail 24 that is in register with the charger 66. Thefixed charging contacts 250 of the charger 66 and/or the ACC chargingcontacts 254 can be resiliently-mounted (e.g., with one or more springs)such that connection into a charging position includes deflecting atleast one positive and at least one negative charging contact 250, 254while driving the trolley 32 along the rail 24. Charging contacts can beprovided on the self-driving trolley 32 and/or a free-rolling trolley36. As illustrated, an upper side of each of the ACC charging contacts254 is convex (e.g., having a flat horizontal center section withdownwardly-angled leading and trailing ends). Respective positive andnegative battery cables 256 extend between the batteries 50 in theenclosure 52 and the ACC charging contacts 254. The cables 256 canpenetrate the enclosure 52, or alternately, can include aquick-disconnect (e.g., plug-in socket) feature at the enclosure 52. Thecharger 66 can be positioned strategically at a dwell location where theACC 28 is naturally stopped for at least a brief period of timeaccording to the regular process served by the conveyor system 20. Forexample, the charger 66 can be positioned at a paint cure station, acooling area, a parts loading station, a parts unloading station, etc.

The conveyor system 20 comprises a control system including thededicated controllers 248 and a master land-based processing unit (LBPU)290 as shown in FIG. 12 . The master LBPU 290 contains the instructionsfor the conveyor system 20 as a whole, including all the on-line ACCs28, and the master LBPU 290 can send updated instructions to any one ormore of the ACCs 28 at any given time. The master LBPU 290 may provideperiodic or continuous instruction to each of the on-line ACCs 28. Insome constructions, the master LBPU 290 may provide no instructions tothe ACCs 28 during normal running after start-up. However, the masterLBPU 290 maintains master control authority over all the dedicatedcontrollers 248. The LBPU 290 can communicate wirelessly with each ofthe ACCs 28, either directly device-to-device (e.g., over a Wi-Fi orother wireless network 294) or indirectly, for example if the network294 includes a plurality of distributed wireless hubs, each provided asa wireless “access point” or “router”, to effectively cover the fullarea of the conveyor system 20 by the network 294. Each ACC 28 includesa wireless communication module 300 communicatively coupled to thenetwork 294 and provided as part of the on-board controller 248. Thewireless communication module 300 enables establishing wirelesscommunication between the master LBPU 290 and the controller 248. Insome constructions, the wireless communication module 300 comprises aWi-Fi module and/or a Bluetooth® module. The wireless communicationmodule 300 can comprise a circuit equipped with an antenna, andoptionally a transmitter, thus forming a transceiver. In someconstructions, the network 294 comprises a mesh network in which some orall of the ACCs 28 communicate directly to each other via the respectivewireless communication modules 300.

Each ACC 28 can be equipped with a battery monitoring/sleep mode module316 coupled to monitor the condition (e.g., voltage) of the on-boardbatteries 50. For example, the battery monitoring/sleep mode module 316includes a monitoring circuit. Maintaining all the ACCs 28 on the rail24 in operational status is of critical importance as the loss of oneACC 28 will hold up the progress of the other ACCs 28 and stop theconveyor system 20 from running further. In order to maintain ACCs 28 inoperational status, each controller 248 therein can be selectively putinto a sleep mode by the battery monitoring/sleep mode module 316. Inthe sleep mode, power draw by the controller 248 is reduced belowoperational level and may be reduced to zero so as to avoid batteryrundown during idle times, since the controller 248 including theinverter 206 may consume substantial power even when not activelydriving the ACC 28 along the rail 24. The sleep mode is separate from anidle mode in which the ACC 28 is stopped and all ACC electronics areactive and ready for running. For example, if there is a temporary(e.g., planned or unplanned) stoppage of the conveyor system 20 whereeach ACC 28 must remain in its current position on the rail 24 untilsuch time as the conveyor system 20 can be restarted, the ACCs 28 may betriggered automatically or deliberately to enter the sleep mode. Thesleep mode can be triggered by an idle sensor (e.g., accelerometer,speed sensor, or position sensor) which can be any type of movementsensor operable to detect lack of movement of the ACC 28. The idlesensor can work in conjunction with a timer to determine a time durationof idleness, whether expected or unexpected. A fixed or variable timethreshold can be used for determining when the ACC 28 is put into itssleep mode. The sleep mode can be commanded by the on-board controller248 and reported to the master LBPU 290, or can be commanded by themaster LBPU 290. Alternately or as an additional option, sleep mode canbe triggered by a manual physical control (switch, dial, button)accessible to a service operator (e.g., on the exterior of the enclosure52). When sleep mode is triggered by a signal sent out from the masterLBPU 290, this can be in response to a preprogrammed routine of themaster LBPU 290 or in response to a human operator's direct request madevia the master LBPU 290. In the sleep mode, the battery monitoring/sleepmode module 316 remains active so that it continues to monitor for awake signal (e.g., from the master LBPU 290) so that the controller 248can be relatively instantly awakened for further operation. The batterymonitoring/sleep mode module 316 can be powered by the batteries 50, andmay in some constructions be the only device powered by the batteries 50when the ACC's on-board controller 248 is put into sleep mode. Thebattery monitoring/sleep mode module 316 can be a very low power devicethat can run off the batteries 50 for multiple days without adverselyaffecting the battery state of charge. In some constructions, thebattery monitoring/sleep mode module 316, in sleep mode and/or normalrunning mode, transmits data regarding the battery condition to themaster LBPU 290. With the battery condition data, the master LBPU 290can issue a master alarm to warn plant personnel in response todetection of a low battery state of charge on one or more ACCs 28 (e.g.,below a predetermined fixed or variable threshold). Such an alarm canallow plant personnel to take action to prevent total battery dischargefor a given ACC 28.

The battery monitoring/sleep mode module 316 can comprise a wirelesscommunication module (e.g., Wi-Fi, Bluetooth®, other wireless radiofrequency communication band such as 900 MHz, or other UHF band, etc.)and a processor. The processor can include the circuit for monitoringthe condition of the on-board batteries 50. As shown in FIG. 12 , thebattery monitoring/sleep mode module 316 can be connected (e.g., viawires) to the batteries 50 to monitor battery condition, and can befurther connected (e.g., via wires) to a relay 320. The batteries 50 canbe monitored individually or as a unit. The battery monitoring/sleepmode module 316 selectively switches the relay 320 on and off to controlwhether or not power is connected from the batteries 50 to the on-boardcontroller 248. The battery monitoring/sleep mode modules 316 may beconnected on the same network 294 that provides the drive control to theACCs 28 (e.g., when drive control and sleep control are provided overWi-Fi channels), or may be connected to an alternate or sub-network(e.g., when the drive control is provided via Wi-Fi and the sleepcontrol is provided via separate UHF band) that also includes the masterLBPU 290.

Further, each of the local controllers 248 of the respective ACCs 28 isprogrammed to carry out independent power level management for its ownon-board batteries 50. Each ACC 28 controller 248 may continuouslymonitor its battery level and current work cycle instructions (i.e.,predicted power requirements based on duration of work cycle, traveldistance, speed and acceleration profiles, etc.) to predictivelyidentify any set of circumstances that could lead to the ACC 28 having abattery level that would leave it unable to complete its work cycle andstranded on the rail 24 away from a charger 66. As such, the controllers248 can be programmed with an adaptive routine or algorithm thatdetermines a low power status (in which the work cycle of the ACC 28 maybe put in jeopardy) that is based only in part on the power level of theon-board batteries 50. The lower power status is further based in parton the current location of the respective ACC 28 along the rail 24and/or a weight of the respective load 100 suspended therefrom. In theevent that the ACC 28 determines that there is a threat to the abilityto complete the work cycle (i.e., predictively, with ample lead time totake countermeasures), one or more actions may be taken to alleviate thethreat. One such action is to communicate to the master LBPU 290 with asystem warning, which may be monitored by a human supervisor. Thewarning can include an identification of the exact identity and/orlocation of the ACC 28 that is threatened. The ACC 28 can also includean externally observable (e.g., visible light or audible alarm)indicator that is triggered to illuminate/sound when the threat isidentified. However, more than calling attention to the problem, the ACC28 may also be programmed to automatically execute a failsafe action,such as automatically adapting its operation in one or more ways, e.g.,re-routing toward a service and/or charging location, revertingautomatically to a power-saving mode of operation, etc. For thispurpose, the rail 24 can include a series of exits or pull-outs wherebyACCs 28 can seamlessly exit the active production line in the event of athreat. If adequately remedied, the ACCs 28 can return automatically tothe active production line. The above mentioned indicator may also beused in times other than battery level threats. For example, one or moreindicators can display a current battery charge level, or overallbattery health status (e.g., a series of lights of one or multiplecolors, alphanumeric and/or symbolic indicia, etc.). The threatidentification of the ACC 28 can operate in conjunction with areprogrammable minimum battery charge level, which corresponds to theminimum battery charge level required to reach the next charging stationor complete the current work cycle (e.g., plus a suitable safetyfactor). When changes occur to the work cycle, or the ACC 28 isreassigned to another work cycle, the battery monitoring system isreprogrammed to the new parameters (e.g., automatically, for examplewith adaptive learning) to ensure proper performance.

A power-saving mode may be a pre-programmed mode of operation that hasone or more alternate sets of instructions for operating the motor 204,differently than a primary or normal operating mode. The alternate setsof instructions can include lower acceleration rates and/or lower fixedspeeds over one or more sections of the conveyor path. The affected ACC28 can also communicate with the master LBPU 290 and/or nearby ACCs 28in the event that the affected ACC 28 going into the power-saving modewill necessarily affect the other ACCs 28 ability to conduct theirnormal programmed work cycle. In some constructions, a transition of anaffected ACC 28 into power-saving mode automatically results (e.g., bydirect communication between ACCs 28, or via the master LBPU 290) intransitioning one or more additional ACCs 28, otherwise unaffected, intoan alternate mode of operation, which may in some circumstances be asympathetic transition into power-saving mode. Once the affected ACC 28is properly managed (to receive additional charge, or be transitionedout of the main conveyor path through the work stations), the ACCs 28may revert to normal operation, and this may be carried out byautomatically sensing corrective action to the affected ACC 28, orthrough a signal from the master LBPU 290, which signal can beautomatically or manually (operator) generated.

Although the conveyor system 20 can include means for automaticallymonitoring ACC battery charge levels and automatically charging thebatteries 50 to prevent rundown to a level that jeopardizes the ACC'sability to complete a given task, unforeseen malfunction or simply agingof the batteries 50 may result in the periodic need to replace thebatteries 50 within the ACC 28. As mentioned above, each ACC enclosure52 can contain multiple batteries 50, each of which can weigh in excessof 20 lbs or 30 lbs (e.g., 50 lbs.). Thus, a significant amount of workis involved in removing and replacing batteries 50. In someconstructions, a maintenance platform is constructed at or elevated tothe height of the enclosure 52 to facilitate a battery swappingoperation. Each battery 50, or the batteries 50 collectively as abattery pack, can have removable connectors that are disengaged toelectrically and physically separate the batteries 50 from the otherelectronics on the ACC 28. In order to physically remove the batteries50 from the enclosure 52, all batteries 50 can rest upon a battery traythat slides into and out of the enclosure 52 when the enclosure isopened. With or without a sliding tray, the batteries 50 can be mountedon a surface with a low friction coating (e.g., UHMW polyethylene orTeflon™) to facilitate easy sliding of the batteries 50 from theenclosure 52 to an external support structure or shelf In someconstructions, the batteries 50, individually or as a pack, areelectrically coupled to the ACC electronics automatically upon physicalinstallation into place within the enclosure 52. For example, thebatteries 50 can have posts or other attached terminal structures thatplug into mating structures, for example sockets, of the enclosure 52 sothat installation of the batteries 50 into the enclosure 52 andattachment with the battery-powered electronics are simultaneouslyaccomplished in a single step.

In another construction, an entire replacement enclosure 52 (e.g.,having the same construction according to the above description) may becoupled to the ACC 28 after removal of the original or first enclosure52. As such, the entire battery pack of the first enclosure 52 isreplaced with a fresh, charged battery pack of the replacement enclosure52. All new electronics of the replacement enclosure 52 are thereforeassociated with the ACC 28 and its motor 204 after removal of the firstenclosure 52 and its electronics. The electronics refer to, for example,the controller 248 with the inverter 206 and the wireless communicationmodule 300, along with the battery monitoring/sleep mode module 316, andrelay 320, among other things. Electrical and physical disconnection ofthe first enclosure 52 can take place on the exterior of the firstenclosure 52, such that it need not be opened during enclosurereplacement, and individual components are not individually replaced,swapped, connected/disconnected. The same is true of the connection ofthe replacement enclosure 52.

In yet another construction, an alternate or secondary enclosure 52′,smaller than the first enclosure 52, can be coupled to the ACC 28 (e.g.,with magnets, straps, threaded fasteners or any other suitable means orcombinations thereof) to power the motor 204 in the event ofinsufficient power of the battery pack in the first enclosure 52 orother malfunction therein. An example is shown in broken lines of FIG. 4. The secondary enclosure 52′ can be a fully functional replacement(e.g., duplicate controller 248) for the first enclosure 52, withouthaving the full battery capacity of the battery pack of the firstenclosure 52. The secondary enclosure 52′ can thus be significantlysmaller, lighter, and easier to handle during an unexpected serviceoperation. The secondary enclosure 52′ can be designed as a rescue packto immediately mobilize an otherwise stranded ACC 28 so that it can bedriven under its own power to a maintenance location off the mainprocess line. For this purpose, the battery 50′ of the secondaryenclosure 52′ can have the same voltage rating as the battery pack ofthe first enclosure 52 while having significantly less capacity, whichmay be a comparison of amp-hour ratings, according to a commonestablished capacity rating methodology. The battery 50′ may also have adifferent, optionally more advanced, battery cell chemistry as comparedto the batteries 50 (e.g., lithium-ion vs. lead-acid). In someconstructions, the secondary enclosure 52′ including all its contentscan weigh less than half that of the first enclosure 52 including allits contents, or even less than 25 percent. In some constructions, thefirst enclosure 52 including all its contents weighs 400 lbs. or more,and the secondary enclosure 52′ including all its contents weighs lessthan 100 lbs. In some constructions, the secondary enclosure 52′including all its contents weighs less than 50 lbs. Similar comparisonsand examples may be true of a direct comparison of the batteries 50 ofthe battery pack of the first enclosure 52 and the battery 50′ of thesecondary enclosure 52′. In some constructions, the secondary enclosure52′ includes one and only one battery 50′. In some constructions, thesecondary enclosure 52′ is utilized as a handheld rescue pack that canbe lifted and coupled to the ACC 28 by a human service worker, withoutrequiring hoisting of the rescue pack with a crane, lift, or otherequipment, thus further limiting the potential down time foradministering the secondary enclosure 52′.

With respect to FIGS. 6 and 7 , it is illustrated that the ACC 28includes at least one sensor 260 configured to monitor the surroundingsadjacent the ACC 28. The illustrated sensor 260 is positioned on theself-driving trolley 32 and aimed in a forward direction, assuming theself-driving trolley 32 operates to pull the remaining free-rollingtrolleys 36. The sensor 260 can be aimed forward as viewed in plan view,and may be aimed with a downward angle (e.g., 30 to 60 degrees downwardfrom the direction of extension of the rail 24) as viewed from the side.The sensor 260 is supported by a bracket 264 on the trolley frame 200.In some constructions, the sensor 260 has a range of available movementup/down, side-to-side, or a combination thereof. Thus, the sensor 260can be adjusted, either manually or automatically (e.g., with one ormore remotely-operable actuators). The sensor 260 can be an ultrasonicproximity detector operable to emit ultrasonic radiation and detectreflected ultrasonic radiation from the immediate surroundings. Thesensor 260 may be operable to detect unexpected foreign objects or apreceding ACC 28 in an unexpected proximity to the ACC 28. The sensor260 communicates output signals to the controller 248, which receivesand interprets the output signals in order to make determinations aboutwhether or not to modify or abort the forward movement of the ACC 28.The controller 248, on the basis of the signals output from the sensor260, can also detect and distinguish a human form from other machinery,such as an ACC 28 or a work piece 48. In some constructions, the sensor260 is a camera, such as an optical or infrared camera. In someconstructions, the sensor 260 is a laser or radar sensor. It is alsocontemplated that the ACC 28 can include multiple sensors operable tomonitor the proximity, and these can include multiple sensors of similartype, or a mixed-type sensor array. It is also noted that sensors can beprovided on more than one side of the ACC 28, either on the self-drivingtrolley 32, or on other parts of the ACC 28.

With primary reference to FIGS. 4, 5, and 7 , the ACC 28 can include atleast one sensor 270 configured to monitor the position of the ACC 28along the rail 24. The sensor 270 can be the idle sensor mentionedabove, or separate therefrom. In the illustrated construction, thesensor 270 is supported on the self-driving trolley 32. However, theoverall occupancy of the ACC 28 along the rail 24 can be determined byconveyor rail sensing performed at any other known position along theACC 28. As shown, the sensor 270 is supported on top of the trolleyframe 200 and is aimed in a direction transverse to the direction ofconveyance and toward the rail 24, just above the adjacent roller 56. Assuch, the sensor 270 is operable to view at least a portion of thecentral vertical web 236. The web 236 has thereon a series of sequentialmarkers or codes 274 in position to be read by the sensor 270. Thesensor 270 may scan at intervals or continuously in order to observe andidentify the markers 274 in order to relay the information to thecontroller 248 to identify the location of the ACC 28 at a given pointin time during operation. The identification of the markers 274 cantrigger changes in drive speed, including stopping and starting the ACC28 in accordance with the necessary processing of the work pieces 48 inthe industrial facility. The real time position tracking of the ACC 28can also be used in conjunction with one or more higher levelcontrollers such as the master LBPU 290, or by device-to-devicecommunication protocol, in order to control or manipulate one or moreoff-rail devices. For example, any one or more of: sprayers, heaters,valves, turntables, doors, grippers, lifts, etc., may be operated inaccordance with the sensed position of the ACC 28. As illustrated, thesensor 270 is a barcode reader or encoder, and the markers 274 areindividual barcodes (e.g., two-dimensional barcodes, such as QR codes).Such a system may be implemented as a PXV Data Matrix Positioning Systemavailable from Pepperl+Fuchs. Voltage to the sensor 270 can be providedfrom the same batteries 50 that power the motor 204, for example througha transformer that steps down the voltage. Power and communication(e.g., Ethernet) wires to the sensor 270, which are shown in FIG. 4 ),can be routed through the flexible conduit 124. Further, a plurality ofmarkers 274 are provided on a continuous strip 278 that is applied, forexample adhesively or magnetically, onto the rail 24. The spacingbetween consecutive markers 274 can be less than 100 mm, less than 50mm, and even less than 25 mm such that high precision location data isavailable from the sensor 270. When the markers 274 are appliedthroughout all portions of the rail 24 in the conveyor system 20, thisenables continuous location tracking of each ACC 28 throughout thesystem 20. In some constructions, the location tracking is performedwith a redundant system, for example also reading the color of eachmarker 274 in addition to the coded value thereof.

In some constructions, each ACC 28 transmits data from its sensor 270 tothe main master LBPU 290 (e.g., on the wireless network 294) asschematically illustrated in FIG. 12 . In some constructions, the ACClocations are determined without the use of wireless triangulation. EachACC 28 includes, for example within the enclosure 52 (FIG. 12 ), thewireless communication module 300 for wireless data transmission of thevarious control signals, including those to and from the main masterLBPU 290, communication with the charger 66, etc. The wirelesscommunication module 300 can be positioned in an electronics section 304of the enclosure 52 that is separate from the battery section 308 thathouses the batteries 50. The respective sections 304, 308 can bephysically separated by a barrier or simply maintained as separateportions of the overall interior space within the enclosure 52. Theelectronics section 304 can also contain communications cables (e.g.,Ethernet) for transporting electronic data among the various electroniccomponents on the ACC 28. In order to accommodate wireless signaltransmission between an interior of the enclosure 52 and the exterior,the enclosure 52 can have at least one non-metallic panel 52A (FIG. 2 ).The remainder of the enclosure 52 may be of steel or other metallicconstruction. The panel 52A can be constructed of thermoplastic, forexample acrylic glass.

FIG. 14 is a simplified exemplary plan view of the conveyor system 20.As shown, the conveyor rail 24 may form a loop for the primary conveyorpath. The path may extend along or through a number of work stations,such as those labeled A-L. It is also noted that the conveyor rail 24may also include bypass paths that bypass certain work stations. Adesignated station 60 is provided for work piece loading and/orunloading. At the loading/unloading station 60 a human worker may loaduntreated work pieces 48 and/or unload treated work pieces 48 forfurther processing or transit. Although the station 60 is shown as asingle station at one end of the conveyor loop, it is possible toprovide separate or multiple stations for loading and/or unloading(e.g., at the opposite end of the loop). It is also noted that the humanworker may be supplemented or replaced by machines including but notlimited to autonomous vehicles, robots, etc. An electrical charger(s)(e.g., charging station 66 described above) for charging the on-boardbatteries 50 of ACCs 28 can be provided in the station 60, as thetrolleys 32 are normally stationary within the station 60 for a periodof time. It is also optional to locate one or more additional chargersat other locations along the conveyor loop. However, in furtherconstructions, whether or not any chargers are located along the processloop, the conveyor system 20 can include at least one dedicated chargingstation 66 along at least one path of the conveyor rail 24. Any of thecharging stations described herein can be contact chargers operable forcharging through mechanical connection of contacts, or alternativelywireless chargers operable for charging wirelessly. Individual chargingstations can be positioned directly above or directly alongside theconveyor rail 24, for example, for interfacing with the self-drivingtrolleys 32 while mounted on the rail 24. The conveyor system 20 caninclude an active fleet of self-driving trolleys 32 (and/or entire ACCs28) that exceeds the number actually in-use to complete the treatmentprocess, such that some are charging while others are working. In otherconstructions, there is no dedicated off-time for any of theself-driving trolleys 32 (and/or entire ACCs 28) while the treatmentprocess is in operation. The batteries 50 may be charged only at processshut-down times, or actively charged at one or more points along theprocess path while the process is in operation.

As described further below, the ACCs 28 provide complete control forindividual self-routing. Each self-driving trolley 32 allows forcomplete control of speed, and acceleration/deceleration profiles of theACC 28 and the work piece(s) 48 thereon, for example, configured tomaximize throughput in a given process work flow along the conveyorsystem 20. This is achieved with the complete absence of any power rail.Compared to conventional power and free systems, the use of the ACCs 28removes the need for the majority of the pneumatic and electricalinfrastructure. Further, it removes the need for wheel turns and rollerturns because there is no power chain as with the current overhead powerand free style conveyor systems. Further, it removes the need for thepower only chain required to close loop a conveyor path (withconventional power and free, 10 to 50 percent of the chain installed ina system is power only required to close loop the conveyor chain).Accordingly, there is no need for conveyor chain drives, conveyor chainlubricators, conveyor chain take-ups, etc. Removing the chainlubricators in particular provides for a much cleaner system and mayexpand the industrial processes that can be served. The noise level ofthe conveyor is also greatly reduced over the noise associated with achain style overhead power and free system.

The on-board controller 248 of each ACC 28 can be configured to providedriving instructions to the on-board motor(s) 204. The drivinginstructions may be executed from a predetermined program stored in aninternal memory. In other words, the ACC 28 can be pre-programmed andoperate within the conveyor system 20 to carry out the treatment processaccording to the designated program instructions (e.g., including traveldistances, slow or fast zones, accel/decel ramp profiles, etc.). TheACCs 28 may be programmed, for example, to accelerate at a lower ratebetween a powder coating application work station and a heating/curingwork station, as compared to acceleration rates elsewhere in the systemas the adhesion between the coating and the work piece 48 is notparticularly strong immediately after application. However, in additionto carrying out the pre-programmed instructions, each ACC 28 may also beconfigured to wirelessly communicate with the master LBPU 290, which canbe accessed via at least one external terminal device 70 (FIGS. 14 and15 ). The external terminal device 70 may take the form of a traditionaldesktop or laptop computer, or mobile computing device such as apersonal electronic device. The external terminal device 70 may providea display and human interface for providing alterations, overrides, orcomplete re-programming of the master LBPU 290, and in turn, the ACCon-board controllers 248. The external terminal device 70 may alsoprovide real time monitoring of performance parameters and/or locationsof any or all of the ACCs 28.

It is noted that the ACCs 28 may include additional powered on-boardfeatures not typically available in a power and free conveyor system.For example, automated collision avoidance systems may be incorporatedinto the ACCs 28 to avoid collisions in the event of a systemmalfunction of one or more of the ACCs 28. In one example, the ACCs 28include respective GPS sensors, or other positional sensors (includingbut not limited to the sensors 260, 270), to identify their respectivelocations and relative position with respect to other ACCs 28. The ACCs28 may be network-connected through any suitable means and monitored forposition, ensuring a minimum spacing distance therebetween, so that anACC 28 will operate to abort its normally programmed routine to stopenergization of the motor(s) 204 and/or apply a brake, external orwithin the motor, if a potential collision is identified. Alternately,or additionally, each of the ACCs 28 can accomplish a similar resulteven without a network, by independently monitoring their immediatesurroundings (e.g., with a proximity sensor, radar sensor, laser sensor,camera, etc.). Although these features can be used in an emergencyfailsafe sense, they may also be utilized as part of the normaloperation. For example, when one of the ACCs 28 is being loaded orunloaded in the station 60, the exact duration of the stop may not beexactly predictable, and may be a function of worker availability orother parameters. The worker may have control of the restarting of thestopped ACC 28 either by providing a signal electronically, or by theuse of a retractable mechanical obstruction 74 (FIG. 14 ) that isdetected by the ACC 28, the ACC 28 stopping upon identifying theobstruction 74 being extended into the travel path. A trailing orupstream ACC 28 approaching the station 60 may detect the presence ofthe downstream ACC 28 and stop before coming into contact, or evenbefore entering the station 60, even if the primary program instructionstell the ACC 28 to proceed for loading/unloading. This decision can bemade based on a signal obtained from direct sensing by sensors on-boardthe ACC 28 and/or based on one-way or two-way communication between theACCs 28, which may be capable of reporting their respective positions toeach other.

In addition to the specific examples provided herein, the ACCs 28 can beoperable with numerous other forms of on-board or off-board diagnostics.Some of these can include: charge condition, battery life or ability tocharge, roller/wheel wear, and physical damage indicators. For example,wear may be detected by monitoring a distance between a referencesurface of the trolley 32 and the conveyor rail 24 since the diameter ofthe wheel 216 directly affects this distance or offset. Alternately,wear may be identified by computing a diameter of the wheel 216 bymeasuring an actual distance traveled (e.g., with the sensor 270 and therail markers 274 or alternately GPS, laser, or identification of fixedintervals) and comparing to a known number of revolutions applied by themotor(s) 204. If the diameter measured is under a predeterminedthreshold, the self-driving trolley 32 may identify itself as having aworn wheel 216 and requiring maintenance or replacement. Such a trolley32 may drive itself (and the associated ACC 28) to a designated servicearea (e.g., the charging station 66 or a separate area) where atechnician can take appropriate action. The ACC 28 may also report itscondition to the master LBPU 290. The ACC 28 may alternately, oradditionally display a coded service indicator (e.g., via externallyvisible light, such as LED, or a display screen) directly at an exteriorthereof.

One of the work stations A-L along the conveyor system 20 can include anenclosure 78 as shown in FIG. 15 . The enclosure 78 can betemperature-controlled such as an oven having heaters to raise thetemperature therein. In other constructions, the enclosure 78 can be aspray booth in which liquid(s) are sprayed or a powder coating boothwhere airborne coating particles exist. The enclosure 78 may or may nothave doors at the upstream and downstream ends. Even with doors capableof closing, the enclosure 78 may or may not form a sealed enclosure inall constructions. The environment within the enclosure 78 may be aharsh or caustic environment due to one or more of extreme temperature,chemical gases or liquids, etc. required to carry out a particularfunction within the treatment process. Though not illustrated here, therail 24 may extend directly through the interior of the enclosure 78,being directly exposed to the actual treatment environment. Theenclosure 52 accompanying each of the self-driving trolley 32 can beexplosionproof, flame-tight, and/or dust-ignitionproof as defined by theNEC. In some embodiments, each enclosure 52 is hermetically sealed fromthe process environment with respect to gases, vapors, and/or liquids(flammable or otherwise). In the illustration of FIG. 15 , the ACC 28does not enter the enclosure 78 but rather drives along the rail 24extending over the top of the enclosure 78, with the work piece supportstructure 44 extending through a slot in the top or roof of theenclosure 78 so that the work pieces are conveyed through the treatmentspace of the enclosure 78 by movement of the ACC 28 along the overheadrail 24. In some embodiments, whether or not the ACC 28 enters a heatedenclosure, the ACC enclosure 52 can have one or more means for heatprotection, in addition to the basic wall construction (e.g., sheet)forming the outer housing of the ACC enclosure 52, to limit heattransfer between the process environment and the internal batteries 50and electrical devices. However, while protective in any one or more ofthe various aspects mentioned above, the enclosure 52 can betransmissive to wireless signals. Alternately, a wireless transmitterand/or antenna may be located on an exterior of the enclosure 52.Examples of heat protection are shown in FIGS. 20A-20D.

FIG. 20A illustrates that at least a bottom wall of the ACC enclosure 52can be shielded with a reflective heat shield 522 to limit the heattransfer to the enclosure 52 and its contents. The heat shield 522 canwrap at least partially up the side walls of the enclosure 52, and mayextend up to the top wall of the enclosure 52. The heat shield 522 canbe bonded to the enclosure 52 wall(s) and/or attached with individualmechanical fasteners. FIG. 20B illustrates that a layer of thermalinsulation 524 may be provided along the bottom wall of the enclosure52, and optionally also along the side walls thereof. The insulationlayer 524 can include foam, fiberglass, and/or other available thermalinsulators. The insulation layer 524 can be separate from the enclosurewalls and coupled thereto (e.g., situated along internal surfaces of theenclosure walls), or may be integrated therewith such that the housingof the enclosure 52 is constructed of insulated wall panels (e.g.,composite panels). As schematically illustrated in FIG. 20B, theinsulation layer 524 does not shield the enclosure 52 from heat, butrather limits heat transfer through the wall to the internal contents.FIG. 20C illustrates another construction in which the enclosure 52 isprovided with a passive heat absorbing device 526. In one construction,the passive heat absorbing device 526 includes a contained quantity ofphase change material adapted to absorb heat (e.g., through melting)during exposure of the enclosure 52 to elevated temperatureenvironments. In another construction, the passive heat absorbing device526 can include a thermoelectric cooler (e.g., Peltier device powered bydedicated batteries or the ACC batteries 50). As schematicallyillustrated, the passive heat absorbing device 526 operates to absorbheat within the enclosure 52, reducing the heat absorbed by thebatteries 50 and other electrical devices. Finally, FIG. 20D illustratesa construction in which the enclosure 52 is provided with an active airconditioning system 528 operating a refrigerant fluid through arefrigeration circuit. In this way, heated air within the enclosure 52can give up heat to the refrigerant of the air conditioning system 528(e.g., evaporating the refrigerant within an evaporator), and theconditioned air can be returned to the enclosure 52. At least part ofthe air conditioning system 528 can be mounted outside the enclosure 52.The active air conditioning system 528 can be operated selectively bythe internal controller 248 or the external control module 70. In someconstructions, the active air conditioning system 528 can have itsoperation triggered automatically based on sensed temperature (e.g.,from a thermocouple measuring internal temperature of the enclosure 52or the enclosure's surroundings) or a detected position, which may ormay not be obtained from the sensor 270. In one example, there may be apredetermined threshold temperature above which the active airconditioning system 528 is triggered to turn on. In another example, theactive air conditioning system 528 is triggered to turn on at apredetermined time or distance upstream of an expected heat exposure,such as that of an oven enclosure. In this way, the interior of theenclosure 52 is pre-charged with cold air, thus entering the heatedenvironment in better condition to limit the maximum internaltemperature. It should also be noted that some or all of the structuresdescribed individually with respect to FIGS. 20A-20D can be used inconcert.

Wireless communications between ACCs 28 and/or between the externalcontrol module 70 and any/all of the ACCs 28 can be radio signals,utilizing radio frequency (RF) transmitters operable to emit RF signalsand antennas operable to receive RF signals. The wireless communicationscan be completed within the context of an established wireless network,for example WLAN, Wi-Fi, etc.

The conveyor system 20 including the ACCs 28 having the self-drivingtrolleys 32 can be used in conjunction with a wide variety of industrialsystems or combinations thereof, including without limitation chemicaltreatment systems, cleaning systems, assembly lines, ovens, chillers,refrigerators, or freezers, and the like.

FIG. 16 illustrates a portion of the conveyor system 20, including astraight rail portion 24S and a curved rail portion 24C downstream ofthe straight rail portion 24S. A number of identical ACCs 28 areillustrated on the straight rail portion 24S. Each ACC 28 supports anyor all of a load bar 40, a work piece support structure 44, and a workpiece(s) 48, collectively referred to herein as a load 100. As shown inthe plan view of FIG. 16 , each load 100 defines an outer perimeter(e.g., rectangular as shown, although the outer perimeter may havealternate shapes). The loads 100 conveyed along the straight railportion 24S are conveyed, as controlled by the self-driving trolleys 32,with a high line density defined, for example, as number of loads perunit length. Line density can be defined in a number of ways, and may beinterchangeable with other similar measures such as carrier-to-carrierspacing (e.g., distance between consecutive ACCs 28, or distance from anself-driving trolley 32 to a nearest downstream trolley 36). In anycase, spacing between loads 100 is kept relatively small and may even beminimized to the point of a practical minimum that will avoid contactbetween loads 100 during a normal amount of longitudinal swinging. Theloads 100 may be conveyed along the straight rail portion 24S at a firstspeed. Although speeds within straight rail portions may vary accordingto different locations within the conveyor system 20, in at least someinstances, the speeds are kept relatively low, especially where thestraight rail sections extend through or along work stations such thatwork station consumables (e.g., fluid of a bath or tank, fluid pumpingenergy, heat energy in an oven, etc.) and/or work stations themselves(e.g., tank or oven lengths, and subsequently components thereof such aspumps, heaters) can be limited or down-sized. However, the existence ofcurved rail portions such as indicated at 24C can lead to the occurrencewhere consecutive loads 100 would interfere with each other. This isshown by the dashed line ACC 28 and associated load 100, which isnavigating the curved rail portion 24C while maintaining the linedensity of the straight rail portion 24S. In order to avoid suchcollisions, each ACC 28 may be accelerated in a transition zone leadinginto the curved rail portion 24C. The transition zone can include adownstream part of the straight rail portion 24S and/or an upstream partof the curved rail portion 24C. Thus, in at least some constructions,the ACCs 28 are accelerated within the curved rail portion 24C. In otherconstructions, the ACCs 28 are accelerated within the straight railportion 24S, prior to reaching the curved rail portion 24C. Theaforementioned acceleration leading into a conveyor path curve, whichincreases carrier-to-carrier gap spacing, may be generally contrary toconventional thought in which loads would desirably be conveyed at theirhighest speeds within straight conveyor runs and then slowed down tonavigate curves. Slowing down for curved conveyor sections can beadvantageous in some circumstances, but carrier-to-carrier spacingcannot be minimized (e.g., line density is lower than could otherwise beachieved) because each carrier must necessarily slow down from thefirst, higher speed to the second lower speed at a given point justprior to the curve, thus reducing the carrier-to-carrier gap spacing.While explained above as a curve visible in plan view (i.e., ahorizontal curve), the same may also be applied to the transitions intoupward or downward slopes, which may be referred to as vertical curves,or elevator sections. The above description of increasing thecarrier-to-carrier gap spacing for the curved rail portion 24C is oneexample of the conveyor system 20 operating with the ACCs 28 programmedto maintain at least two different minimum carrier-to-carrier spacingdistances in different conveyor sections.

In addition to the navigation of curved sections within the conveyorsystem 20, certain aspects of the invention may include transitions thatinclude more abrupt directional changes, such as a side shift orvertical shift at a defined switch point. Such a shift can in someconstructions include a rotary turntable rail portion 24T having movableconveyor rail portion(s) thereon as shown in FIG. 17 . As such, theconveyor can include a true intersection point or angled turn. Althoughtwo opposite 90-degree turns from the original incoming conveyor railpath are illustrated, other combinations are optional, includingdifferent numbers of outlet paths and differently-angled outlet paths.The self-driving trolley 32 can drive the ACC 28 onto the turntable railportion 24T, then stop and pause while the turntable rotates to orientthe ACC 28 to the desired outlet path, which information may bepreprogrammed into the master LBPU 290, or optionally directed from theACC 28 as it arrives at the turntable rail portion 24T. The self-drivingtrolley 32 then drives the ACC 28 off the turntable rail portion 24Tonce aligned with the desired outlet path. As shown in FIG. 18 , theconveyor system 20 can include an elevator rail portion 24E thatsupports at least one ACC 28 for vertical movement along a track toallow vertical movement directly away from an upstream portion of therail 24, which may be a horizontal rail portion. The self-drivingtrolley 32 can drive the ACC 28 onto the elevator rail portion 24E, thenstop and pause while the elevator rail section is driven to a downstreamportion of the rail 24 that is at a different height, higher or lowerthan the incoming portion of the rail 24. In some constructions, a drivesystem (chain, belt, gear train, etc.) that moves the elevator railportion 24E along the vertical track can be powered from theself-driving trolley 32, thus providing a cart-powered lift, such that adrive source need not be integrated into the conveyor infrastructure. Inother words, the drive system used to power part of the conveyorinfrastructure may receive drive power from a driven wheel of theself-driving trolley 32 positioned thereon. Similarly, a drive system(chain, belt, gear train, etc.) that moves the turntable rail portion24T of FIG. 17 can be powered from the self-driving trolley 32 such thata drive source need not be integrated into the conveyor infrastructure.

Although it is mentioned above that the various ACCs 28 within theconveyor system 20 can have independent speeds and acceleration ordeceleration profiles, it is also noted that the self-driving trolleys32 enable more diverse types of movements among the ACCs 28 within thesame conveyor system, and more particularly within a single rail 24thereof. For example, given ample spacing, different ACCs 28 or groupsthereof may move in opposite longitudinal directions along the rail 24.For example, a given ACC 28 may traverse two work stations and thencycle back through those work stations while a further-upstream ACC 28occupies a single further-upstream work station or moves in adownstream-only direction toward the further-downstream ACC 28. It isalso envisioned that one or more ACCs 28 may oscillate forward andbackward along a conveyor rail 24, e.g., within one or more workstations, while other ACCs 28 on the same rail 24, including at leastone directly adjacent ACC 28, are stationary or moving in a singleforward direction.

In areas where the self-driving trolleys 32 are responsible for drivingthe ACCs 28 through a work station, and where different types of loads100 are being conveyed, the self-driving trolleys 32 can traverse thework station with different speed profiles based on at least onecharacteristic of the load supported (e.g., responsive to weight, typeof applied coating on the work piece(s), etc.). Such information aboutthe load 100, either provided as a data transmission to the ACC 28 orsensed locally by the ACC 28, can be stored in a memory of theself-driving trolley 32 and used to execute corresponding programinstructions while driving through the work station(s). In some aspects,characteristics of the load 100 may be sensed directly by one or moresensors of the self-driving trolley 32 so as not to require theconveyance of outside information to the self-driving trolley 32. Forexample, a load cell can be incorporated into the ACC 28 or thestructures that suspend the load 100 from the ACC 28. In either case,the load cell can be in communication with the ACC's internal controller248 to provide electrical signals indicative of the sensed weight of theload 100. Providing load-dependent ACC 28 operation can include settingor updating a set of instructions (e.g., location-based speed andacceleration/deceleration profiles) programmed to the internalcontroller 248.

In some constructions, it is not only the speed of load conveyancethrough a work station that can be independently managed, butalternately or additionally, the load-to-load gaps. Such gaps can bechanged by independently controlling acceleration and deceleration ofadjacent ACCs 28. One specific example is the conveyance of loads 100 toone or more paint spray work stations in a close-packed configurationwith relatively small gaps therebetween. Although the ACCs 28 may beconveyed toward the paint spray work station at relatively high speedfrom an upstream station, speed of a downstream one of the ACCs 28 maybe increased as it approaches the paint spray station to create anincreased gap to limit the effects of overspray among adjacent loads100. Once the requisite gaps are created, the ACCs 28 may move throughthe paint spray work station at a reduced speed more conducive toapplying the paint. Paint spray represents one example of a spray workstation, of which there are others, and these aspects of the inventionalso apply to other work stations other than those where the load 100 issprayed.

In some constructions, an ACC 28 can include at least two self-drivingtrolleys 32. In some cases, two self-driving trolleys 32 exert driveenergy to move the ACC 28 along the rail 24. However, one of theself-driving trolleys 32 may be left in a neutral or free-wheeling stateduring normal operation while the other is responsible for driving alongthe rail 24. In certain instances, the second self-driving trolley 32may be utilized to provide additional functionality. One such example,referred to as diagonal banking, is illustrated in FIG. 19 . As shown, asecond conveyor rail 24 is branched from the first conveyor rail 24. Thetwo self-driving trolleys 32 of a single ACC 28 can then drive along twoparallel rails 24 to effectively turn the loads 100 perpendicular totheir normal conveyance direction. Assuming the loads 100 are longer(length L) in the normal conveyance direction (in which the load bars 40extend parallel to the rail 24), turning of the loads 100 to aperpendicular orientation in which the carrier width W extends along theconveyance direction can further maximize the load density forclose-packing of loads 100 beyond what is possible when the ACCs 28 arein their normal orientation along one rail 24. The substantial increasein load density, which corresponds to the ratio of length L to width W,can be at least 20 percent, and optionally 30 percent or more, 40percent or more, or even 50 percent or more. It is noted that the lengthL and width W are labeled in FIG. 19 as being the dimensions of the load100, which is the relevant dimension for avoiding contact when the load100 is both longer and wider than the structure of the ACC 28 carryingthe load 100. However, in other scenarios, the length L and width W canbe the actual length and width of the ACC 28, and the above text can beinterpreted as such. One or both of the length L and width W of the ACC28 may in some cases be larger than the corresponding load dimension(s).Finally, while FIG. 19 relates to an embodiment having multipleself-driving trolleys 32, it is also conceivable to turn the ACCs 28from one to two rails 24 as shown and to drive the ACCs 28 along the tworails 24 as shown on the right side of FIG. 19 by way of a singleself-driving trolley 32, along with a free-rolling trolley 36. Forexample, the various load bars 40, 40A, 40B may be lockable into a fixedorientation matching the desired configuration, e.g., by selectivelylocking the respective pivots 42.

Unless otherwise noted or expressly prohibited, any of the separatelydisclosed features or embodiments may be combined together in variousforms, resulting in additional embodiments not explicitly referred toherein. These and other adaptations will be recognized as being withinthe spirit and scope of the present disclosure.

What is claimed is:
 1. A conveyorized industrial system comprising: atleast one work station including a heated oven chamber; a fixed,non-powered rail defining a conveyor path including an oven zone,wherein the rail extends through or over the heated oven chamber; and anautomated conveyor carrier (ACC) including a self-driving trolley havingan on-board motor, the ACC being suspended from the rail by theself-driving trolley and drivable along the rail by the self-drivingtrolley, wherein the ACC further comprises an enclosure containing oneor both of an inverter and a battery, the enclosure having a walldefining an interior space of the enclosure, and wherein a heatprotection system is provided in addition to the wall, the heatprotection system operating to limit an internal temperature of theenclosure during transport along the oven zone.
 2. The conveyorizedindustrial system of claim 1, wherein the heat protection systemincludes a heat shield coupled to an exterior surface of the enclosureat least at a bottom side of the enclosure.
 3. The conveyorizedindustrial system of claim 1, wherein the heat protection systemincludes a layer of insulation within the wall of the enclosure.
 4. Theconveyorized industrial system of claim 1, wherein the heat protectionsystem includes a thermoelectric cooler having a cold side exposed tothe interior space of the enclosure.
 5. The conveyorized industrialsystem of claim 1, wherein the heat protection system includes an airconditioning system including a refrigeration circuit, the airconditioning system operable to deliver conditioned air to the interiorspace of the enclosure.
 6. The conveyorized industrial system of claim1, wherein the heat protection system includes a passive heat absorbingdevice including a contained quantity of phase change material.
 7. Theconveyorized industrial system of claim 1, wherein the enclosure isNEC-rated as at least one of: explosionproof, flame-tight, and/ordust-ignitionproof.
 8. The conveyorized industrial system of claim 1,wherein the enclosure contains the inverter and a battery, as well as acontroller and a wireless transceiver, within the interior space.
 9. Theconveyorized industrial system of claim 1, wherein the ACC is furthersuspended from the rail by at least one free-rolling trolley.
 10. Theconveyorized industrial system of claim 1, wherein the ACC is one of aplurality of ACCs, each of which includes a self-driving trolley havingan on-board motor and is suspended from the rail by the self-drivingtrolley and drivable along the rail by the self-driving trolley, anenclosure containing one or both of an inverter and a battery, theenclosure having a wall defining an interior space of the enclosure, anda heat protection system in addition to the wall, the heat protectionsystem operating to limit an internal temperature of the enclosureduring transport along the oven zone.
 11. A conveyorized industrialsystem comprising: at least one work station including a heated ovenchamber; a fixed, non-powered rail defining a conveyor path including anoven zone, wherein the rail extends through or over the heated ovenchamber; and an automated conveyor carrier (ACC) including aself-driving trolley having an on-board motor, the ACC being suspendedfrom the rail by the self-driving trolley and drivable along the rail bythe self-driving trolley, wherein the ACC further comprises an enclosurecontaining an inverter, a battery connected to the inverter, acontroller connected to the inverter, and a wireless transceiverconnected to the controller, the enclosure having a wall defining aninterior space of the enclosure, and wherein a heat protection system isprovided in addition to the wall, the heat protection system includingan air conditioning system operating a refrigerant fluid through arefrigeration circuit, the air conditioning system operable to deliverconditioned air to the interior space of the enclosure to limit aninternal temperature of the enclosure during transport along the ovenzone.
 12. The conveyorized industrial system of claim 11, wherein theACC is further suspended from the rail by at least one free-rollingtrolley.
 13. The conveyorized industrial system of claim 11, wherein theACC is one of a plurality of ACCs, each of which includes: aself-driving trolley having an on-board motor and is suspended from therail by the self-driving trolley and drivable along the rail by theself-driving trolley, an enclosure containing an inverter, a batteryconnected to the inverter, a controller connected to the inverter, and awireless transceiver connected to the controller, the enclosure having awall defining an interior space of the enclosure, and a heat protectionsystem in addition to the wall, the heat protection system including anair conditioning system operating a refrigerant fluid through arefrigeration circuit to deliver conditioned air to the interior spaceof the enclosure.
 14. The conveyorized industrial system of claim 11,wherein operation of the air conditioning system is configured to betriggered automatically based on one or both of: a sensed temperatureinternal to the enclosure or the enclosure's surroundings as reported tothe controller from at least one temperature sensor in communicationwith the controller, or a detected position of the ACC with respect tothe oven zone as reported to the controller from at least one positionsensor in communication with the controller.
 15. The conveyorizedindustrial system of claim 11, further comprising one or both of: alayer of insulation within the wall of the enclosure, and a heat shieldcoupled to an exterior surface of the enclosure at least at a bottomside of the enclosure.
 16. A conveyorized industrial system comprising:at least one work station including a heated oven chamber; a fixed,non-powered rail defining a conveyor path including an oven zone,wherein the rail extends through or over the heated oven chamber; and anautomated conveyor carrier (ACC) including a self-driving trolley havingan on-board motor, the ACC being suspended from the rail by theself-driving trolley and drivable along the rail by the self-drivingtrolley, wherein the ACC further comprises an enclosure containing aninverter, a battery connected to the inverter, a controller connected tothe inverter, and a wireless transceiver connected to the controller,the enclosure having a wall defining an interior space of the enclosure,and wherein a passive heat protection system is provided in addition tothe wall, the passive heat protection system including a heat absorbingdevice including a contained quantity of phase change material.
 17. Theconveyorized industrial system of claim 16, wherein the ACC is furthersuspended from the rail by at least one free-rolling trolley.
 18. Theconveyorized industrial system of claim 16, wherein the ACC is one of aplurality of ACCs, each of which includes: a self-driving trolley havingan on-board motor and is suspended from the rail by the self-drivingtrolley and drivable along the rail by the self-driving trolley, anenclosure containing an inverter, a battery connected to the inverter, acontroller connected to the inverter, and a wireless transceiverconnected to the controller, the enclosure having a wall defining aninterior space of the enclosure, and a passive heat protection system inaddition to the wall, the passive heat protection system including aheat absorbing device including a contained quantity of phase changematerial.
 19. The conveyorized industrial system of claim 16, furthercomprising one or both of: a layer of insulation within the wall of theenclosure, and a heat shield coupled to an exterior surface of theenclosure at least at a bottom side of the enclosure.
 20. Theconveyorized industrial system of claim 16, further comprising athermoelectric cooler having a cold side exposed to the interior spaceof the enclosure.